| ZIP Codes: | 19 ZIP Codes (15 Standard, 3 PO Box, 1 Unique) [See All] |
| Area Code: | 603 |
| Timezone: | Eastern (GMT -05:00) |
| Local Time: | 2:13:09 PM |
| Population: | 130,989 [See All] |
| FIPS: | 33017 |
| CBSA: | Boston-Cambridge-Newton, MA-NH |
| Land Area: | 363 sq mi |
| Water Area: | 47 sq mi |
| Coordinates: | 43.2750, -70.9853 |
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130,989 residents live across 19 ZIPs covering 363 sq mi, served by 14 distinct USPS-recognized cities.
Population moved from 122,820 to 130,989 from 2014 to 2024 — a +6.7% change. 11 ZIPs gained residents, 4 lost.
The county's wealthiest ZIP 03823 (Madbury, $148,365 median) and poorest ZIP 03835 (Farmington, $66,982) are 14.5 miles apart — a 2.2× income gap across local geography.
Median home values vary 1.9× across this county — from $268,800 in 03868 (Rochester) to $504,300 in 03824 (Durham).
Density varies 19× across the county — from 65 people/sq mi in 03855 (New Durham) to 1,213 in 03878 (Somersworth).
Most of the decade's growth concentrated around Rochester — top growth ZIPs averaged +11.1% over the past ten years ( 03868 , 03823 and 03867 ).
Educational attainment ranges from 16.4% bachelor's+ in 03835 (Farmington) to 75.4% in 03824 (Durham) — the breadth of educational profiles across the area.
Within New Hampshire, this is the #4 most populous of 11 counties and ranks #4 for median household income with the #4 fastest decade growth .
Hosts 1 single-entity Unique ZIP: 03822Liberty Mutual Insurance .
Weighted by population, the typical household earns about $95,511 across the county — reflecting what a typical resident sees, not a simple ZIP average.
39.5% of adults age 25+ hold a bachelor's degree or higher (35,121 of 88,934 reporting).
15 Standard delivery, 3 PO Box only, 1 single-entity Unique ZIPs serve this county.
1 ZIP in this county where more than 60% of adults 25+ hold a bachelor's degree — typically college campuses, research enclaves, or tech corridors.
| ZIP | City | Type | Population | Median Income | Area (sq mi) | 10-yr Growth |
|---|---|---|---|---|---|---|
| 03820 | Dover | Standard | 33,440 | $94,897 | 29.7 | 10.2% |
| 03867 | Rochester | Standard | 22,732 | $78,674 | 29.2 | 10.8% |
| 03824 | Durham | Standard | 15,080 | $124,056 | 24.8 | -0.7% |
| 03878 | Somersworth | Standard | 12,205 | $75,136 | 10.1 | 3.2% |
| 03825 | Barrington | Standard | 9,489 | $110,323 | 48.9 | 10.4% |
| 03835 | Farmington | Standard | 6,804 | $66,982 | 37.1 | -0.3% |
| 03868 | Rochester | Standard | 6,133 | $81,530 | 8.7 | 11.4% |
| 03861 | Lee | Standard | 4,576 | $131,579 | 20.2 | 5.0% |
| 03851 | Milton | Standard | 4,333 | $93,412 | 27.4 | 10.1% |
| 03884 | Strafford | Standard | 4,306 | $122,105 | 51.1 | 7.2% |
| 03839 | Rochester | Standard | 4,279 | $88,346 | 7.6 | 8.2% |
| 03855 | New Durham | Standard | 2,748 | $100,194 | 42.0 | 3.8% |
| 03869 | Rollinsford | Standard | 2,456 | $87,215 | 6.9 | -0.4% |
| 03823 | Madbury | Standard | 2,203 | $148,365 | 12.1 | 11.1% |
| 03852 | Milton Mills | Standard | 205 | $154,583 | 6.8 | -68.7% |
| 03866 | Rochester | PO Box | — | — | 0.0 | — |
| 03821 | Dover | PO Box | — | — | 0.0 | — |
| 03822 | Dover | Unique | — | — | 0.0 | — |
| 03815 | Center Strafford | PO Box | — | — | 0.0 | — |